"Remember that thou keep holy the sabbath day.  Six days shalt thou labor, and shalt do all thy works.  But on the seventh day is the sabbath of the Lord thy God:  thou shalt do no work on it, thou nor thy son, nor thy daughter, nor thy manservant, nor thy maidservant, nor thy beast, nor the stranger that is within thy gates.  For in six days the Lord made Heaven and earth, and the sea, and all things that are in them, and rested on the seventh day:  therefore the Lord blessed the seventh day, and sanctified it."  (Exodus 20:8-11)

1. What is the Third Commandment?

   Remember thou keep holy the Sabbath Day.
2. What does the Third Commandment oblige you to do?
1. To attend Mass every Sunday and Holy Day of Obligation.
2. To avoid all unnecessary manual ("servile") work or shopping on Sundays and Holy Days.
3. What are the six Holy Days of Obligation in the United States?
1. Christmas (Dec. 25), feast of the Birth of Jesus Christ.
2. New Year's Day (Jan. 1), Circumcision of Jesus Christ.
3. Ascension Thursday (40 days after Easter).
4. Assumption of the Blessed Virgin Mary (Aug. 15)
5. All Saints Day (Nov. 1)
6. Immaculate Conception (Dec. 8).

In Canada, Epiphany (Jan. 6) is a Holy Day, but the Feast of the Assumption is not.

4. What kind of sin is it to miss Mass on Sunday or a Holy Day?

   To miss Mass on these days through your own fault and without sufficient reason is a mortal sin.
5. What kind of sin is it to be late for Mass on a Sunday or Holy Day of Obligation?

   If, through your own fault, you come into the church --
1. Anytime before the priest takes the veil off the chalice, you commit a venial sin, unless you stay for the missed part in another Mass.
2. Anytime after the priest takes the veil off the chalice you commit a mortal sin, unless you stay for another entire Mass.

The priest removing the veil from the chalice marks the beginning of the Offertory, the first of the three principal parts of the Mass.

6. Are you ever excused from the obligation of hearing Mass?

   Yes, but only for a serious reason.

Examples:  Sickness, caring for a sick person, long distance from the church, necessary work.

7. Can a priest excuse you from the obligation?

   Yes, your pastor, or the priest in Confession, can excuse you for a sufficient reason.

But it is not necessary to ask a priest if you know you have a sufficient reason.

8. What does the Third Commandment oblige you to do as a parent?

   You have the serious obligation to see that your children attend Mass on Sundays and Holy Days.
9. What kind of work is forbidden on Sundays and Holy Days?

   Manual ("servile") work, unless it is necessary, such as making beds, washing dishes, taking care of the sick.
10. Is it wrong to enjoy sports and other recreation on Sunday?

   No, unless they interfere with your religious obligations.

Examples:  Movies, dancing.

11. What kind of sin is it to do unnecessary physical work on Sunday or a Holy Day of Obligation?

   A mortal sin, if you work for a substantial length of time; a venial sin, if for a briefer length of time.

Unnecessary physical work is considered to be a mortal sin if it totals about 2.5 to 3 hours of hard work.

NOTE...
   The Church changed the Lord's Day from Saturday to Sunday because Our Lord rose from the dead on Sunday and the Holy Ghost came down upon the Apostles on Pentecost Sunday.  Also, Sunday is the first day of the week and Saturday the last.  It is altogether more fitting in the New, more perfect Law or Testament that the Church consecrate the first day of the week to the Lord, rather than the last.  Thus we give God the "first fruits" of our week.